The present invention relates generally to methods and systems for separating metals from articles and assemblies, including electrical components, in which two or more different metals are physically or structurally combined. In particular the present invention is directed to a method of using a tunnel kiln furnace to separate metals from various articles and assemblies.
Metal wastes which are desired to be recycled can include materials, articles, assemblies and/or components that comprise physical or structural mixtures or combinations of two or more different metals. These mixtures or combinations of different metals can be difficult to separate using conventional techniques such as physical mechanical or manual separation. While the individual materials, if separated, can have a high commercial value, the mixed or combined materials generally have a significantly lower commercial value.
“Copper meatball” is the term given to copper wound electrical components of automobiles by automobile recyclers. “Copper meatballs” that are recovered from automobile shredding operations and motor vehicle scrapping operations and include motor armatures, field cores, transformers and similar electrical components. These “copper meatballs” are also known as “SHELMO” within the ferrous shred industry and have relatively low value. If the copper and iron could be economically separated from “copper meatballs” the value will be increased significantly. However to date no economical process exists to separate the copper and iron from “copper meatballs.” In fact one current manner of separating the copper and iron from “copper meatballs” involves shipping them to low employment wage counties where workers manually separate the copper and iron by hand.
In the United States alone there are more than 10 million tons of automobiles that are shredded annually. The shredding of these automobiles produces an estimated 20 to 25 pounds of “copper meatballs” per automobile. The result is that more than 100,000 tons of “copper meatballs” are available for recycle every year. The ratio of copper to iron in “copper meatballs” can vary; however, a conservative estimate of 10% copper in “copper meatballs” means there will be more than 10,000 tons of copper available for recovery annually. This represents a significant potential value.
The separation of materials or articles that are comprised of two or more metals will be proportionally challenging based on how tightly the two or more metals are physically or structurally combined. In the case of “copper meatballs” copper wire is typically wound tightly around the iron core of electrical components such as motor armatures, field cores, transformers, and the like. Since the physical separation of these materials is very costly, the current practice for shredder companies is to sell the “copper meatballs” at a fraction of the value of the individual copper and iron components. The physical separation of materials is possible, but is very time consuming.
U.S. Pat. No. 3,776,718 to Leak et al. discloses a process to recover copper and steel from scrap which is rather complicated in that it requires that the scrap first be treated with a chemical reagent such as sodium sulfates and silicates, then dried and then immersed in a molten medium such as a salt, slag or glass.
The present invention provides a method that separates copper from the iron in “copper meatballs” by melting the copper and leaving the iron as a solid material. Such a simple selective melting of the lower melting metal according to the present invention is much more effective and economical to perform than previous separation methods.